1. Field of the Invention
The present invention relates to a disk playback apparatus of the type in which a disk pulled out from one of a plurality of disk holders stacked one on another is chucked on a drive base unit so as to be subjected to playback operation. More particularly, the present invention pertains to a disk playback apparatus in which the driver base unit is moved into a space that is formed by vertically moving at least one of the stacked disk holders, rather than by horizontally moving the entirety of the stack of disk holders.
2. Description of the Related Art
Hitherto, widely used are disk playback apparatuses of the type in which a disk is selected from a group of disks accommodated in a magazine and is automatically conveyed and subjected to playback operation. This type of disk playback apparatus has an auto-changer mechanism which automatically selects the disk to be conveyed and played back, in accordance with a predetermined program and based on instructions given by a user through operation buttons or through a remote controller.
In general, each of the disks accommodated in the magazine is individually held by an exclusive disk holder designed differently in accordance with the diameter of the disk. The disk selected by the auto-changer mechanism is horizontally conveyed to a position on the drive base unit while being located by the exclusive disk holder, thereby being played back by the drive base unit. The driver base unit is movable up and down, and is set to a level corresponding to the selected disk, before the selected disk is drawn out.
This type of disk playback apparatus has excellent operability because a desired one of a plurality of disks accommodated in the magazine can automatically be brought into playback operation simply by being selected, without requiring independent manual operations for inserting and ejecting the disk. The described disk playback apparatus, however, has a problem in that a laborious work is required for demounting and mounting the magazine for setting a new disk in the magazine, when the user wishes to playback such a new disk that has not been accommodated in the magazine. This laborious work is necessary even when only one of the disks in the magazine is to be replaced with the new disk, while other disks remain in the magazine so as to be played back subsequent to the playback of the newly set disk.
The disk playback apparatus employing a detachable magazine tends to have greater dimensions particularly when a large number of disks are to be set in the magazine. Consequently, the number of disks that can be set in the magazine is undesirably limited particularly when the space for accommodating the playback apparatus is restricted as in the case of automotive disk playback apparatuses. This problem is more fully discussed below.
A magazine, which is detachable from the main part of the disk playback apparatus, is required to have strength large enough to protect disks accommodated therein. Consequently, wall thickness, as well as overall dimensions, of the magazine is rendered large. In order to guide horizontal movement of each disk holder in the magazine, guide rails are formed on the opposing inner surfaces of the magazine, thus further increasing the magazine wall thickness. The guide rails also serve to increase the pitch or heightwise distance between adjacent disk holders, resulting in an increase in the overall height of the magazine. When a disk is drawn out from the magazine for playback operation, it is necessary that an ample space is available on at least one side of the disk. Provision of such a space inevitably increases the height of the magazine, corresponding to the number of the disks employed or, in case of an automotive disk apparatus which has to be installed in a limited space, the number of the disks that can be set in the magazine is undesirably reduced.
Under these circumstances, efforts have been made to develop a disk playback apparatus of the type devoid of any detachable magazine. More specifically, in this type of disk playback apparatus, a plurality of disk holders are stacked in the apparatus without the intermediary of a magazine, and disks inserted through the disk insertion slot are automatically set on the disk holders and are also automatically ejected.
This type of disk playback apparatus enables the user to easily replace the disks, by virtue of automatic setting and ejection of the disks. More specifically, the user is required only to operate a button or a key for ejecting the disk to let the disk be ejected, followed by manual insertion of the disk into the disk insertion slot. Further, the overall dimensions of the disk playback apparatus are reduced as compared with the apparatuses that employ magazines.
Thus, the disk playback apparatus which is being developed enables automatic setting and ejection of disks into and out of the stack of disk holders, offering advantages such as ease of operation and reduction in the dimensions. The effect to reduce the dimensions, however, is still insufficient, insofar as the apparatus relies on horizontal reciprocal arrangement in which the disk holders are constructed and arranged to reciprocate in horizontal directions.
More specifically, when such a horizontal reciprocal arrangement is used, it is necessary that a distance which is at the smallest equal to the disk radius be preserved between the point where the disk center is located when the disk is in the accommodated position and the point where the disk center is located when the disk has been moved to the position on the drive base unit. This poses a limit to the reduction in the horizontal dimension of the apparatus. Further, reduction in the dimension is limited also in the heightwise direction, because of the necessity of the guide grooves and rails for enabling the reciprocal motions of the disk holders.
In contrast to the above-described horizontal reciprocal arrangement, an arrangement referred to as xe2x80x9cstack/separation arrangementxe2x80x9d has recently been proposed, in which a drive base unit is introduced into a space that is formed by moving upward or downward a disk holder or disk holders above or below a separation position which is assumed on one side of the selected disk holder. This stack/separation arrangement can effectively reduce the horizontal dimensions of the whole apparatus without increasing the heightwise dimensions as compared to the horizontal reciprocal arrangement, insofar as the movements of the disk holders are concerned. A brief description will be given below in this respect.
In accordance with the stack/separation arrangement, the disk holders are initially arranged in a packed manner, such that adjacent disk holders contact each other or positioned in the close proximity of each other. For the purpose of playing back the selected disk, the disk holders that are on the upper side of the selected disk are moved upward as a unit, or the disk holders that are on the lower side of the selected disk are moved downward as a unit, whereby a space for receiving the drive base unit is formed on the upper side or lower side of the selected disk. Likewise, if the selected disk is the topmost or lowermost one of the stacked disk holders, all the disk holders are moved downward or upward as a unit, whereby the space for receiving the drive base unit is formed. The height of this space is greater than the distance between two adjacent disk holders in the horizontal reciprocal arrangement, but is almost equal to the sum of the distances of the consecutive adjacent disk holders.
The stack/separation arrangement requires horizontal reciprocal movement of the drive base unit, instead of the horizontal reciprocation of the disk holders. The horizontal position of the drive base unit where it can playback the disk may be determined arbitrarily such that it overlaps the disk holder. It suffices only to retract the drive base unit to a position where it does not interfere with the vertical movement of the disk holders. Therefore, the horizontal dimensions of the apparatus can be minimized by reducing as possible the dimensions of the drive base unit.
The stack/separation arrangement, however, requires not only a mere vertical movement of the disk holders but n operation for selecting the separation position where the space for accommodating the drive base unit is to be installed. In addition, a variety of patterns of vertical movements of the disk holders are to be implemented, depending on the separation position. Consequently, a complicated control is required to achieve many different patterns of movements of the disk holders, which in turn necessitates a complicated actuating system. A complicated control and hence a complicated actuating mechanism are also necessary for moving the drive base unit not only vertically but also horizontally. Further, a difficulty is encountered by properly controlling the timings of operations of the whole mechanism for implementing the complicated actions of the disk holders and the drive base unit.
Accordingly, a first object of the present invention is to provide a disk playback apparatus which excels both in reliability and operability and which relies on the stack/separation arrangement of the disk holders implemented by a compact and simple structure, while performing, at proper timings, a series of operations including selection of the separation position and execution of the separating operations based on the position of the disk to be played back, control of the level of the drive base unit, insertion of the drive base unit into the space formed as a result of the separation, chucking of the disk, and so forth.
A second object of the present invention is to provide a disk playback apparatus which is so small and simple as to be suitably accommodated in a desired space on a vehicle, thus suiting to use on a vehicle.
To these ends, according to one aspect of the present invention, there is provided a disk playback apparatus, comprising: a disk insertion section through which disks are inserted and ejected; a plurality of disk holders each holding one of the disks; a drive base unit for playing back a desired disk; disk holder lifting means for selecting the disk holder holding the desired disk and for lifting or lowering all or part of the disk holders so as to form a space for accommodating the drive base unit; drive conveyance means for moving the drive base unit between the space formed as a result of the lifting or lowering of the disk holders and a space adjacent to the disk insertion section; disk loading/ejection means for pulling inward the disk that has been inserted through the disk insertion section to enable the disk to be held by the disk holder, and for receiving the disk from the disk holder and ejecting the received disk to the disk insertion section; a stage unit for supporting the disk holder lifting means and the drive base unit; and stage lifting means for lifting and lowering the stage unit in accordance with the position of the selected disk holder.
Thus, the disk playback apparatus of the present invention is characterized by the use of the stage unit for supporting the disk holder lifting means and the drive base unit, and the stage lifting means for lifting and lowering the stage unit in accordance with the position of the selected disk holder.
In accordance with this arrangement, since the disk holder lifting means are supported together with the drive base unit on the stage unit, it is possible to simultaneously achieve both the selection of the disk holders to be lifted or lowered and the positioning of the drive base unit that is to be inserted, by a single lifting or lowering motion of the stage lifting means. Thus, components of the mechanisms are accurately aligned with one another, and the timings of operations of the components are adequately determined, despite the simplified construction of the apparatus.
Preferably, the disk loading/ejection means are provided on a portion of the drive base unit adjacent the disk insertion section.
To enable loading or ejection of the disk, it is necessary to lift or lower the disk holders so as to select a disk holder to which a disk is to be loaded or from which a disk is to be ejected, and to bring the selected disk holder into alignment with the disk loading/ejection means. Since both the disk holder lifting means and the disk loading/ejection means are carried by the stage unit, it is possible to accurately bring the selected disk holder into alignment with the disk loading/ejection means, subsequent to the selection of the disk holder.
The arrangement may be such that the disk holder lifting means includes a cam member having an inclined cam surface, the cam member being carried by the drive base unit for movement in the directions for loading and ejecting the disk, each disk holder having a cam follower contacting with the cam surface of the cam member and urged in at least one of upward and downward directions in accordance with the movement of the cam member.
In accordance with this arrangement, the disk holders are lifted or lowered as a result of the movement of the inclined cam surface in the direction of loading and ejection of the disk. It is therefore possible to effect up or downward movement of the disk holders with a small stroke of movement of the cam member. Consequently, the dimension of the mechanism is reduced in the disk loading/ejection directions, thus realizing a compact construction of the payback apparatus.
The disk payback apparatus may be arranged such that the cam surface of the cam member is stepped to provide stages corresponding to the positions of the disk holders which are lifted and lowered.
In accordance with this arrangement, each stage of the stepped cam surface can securely hold each disk at a predetermined position, thus offering high positioning accuracy for the disk holders.
The cam member may include a guide cam continuing from the cam surface, the guide cam serving to guide the cam follower of the disk holder until the disk held by the disk holder is brought to a position where the disk is played back by the drive base unit.
With this arrangement, the lifting and lowering operations of the disk holders caused by the movement of the cam member in the direction of loading or ejection of the disk not only causes separation of the disk holders and positioning of a selected disk holder at the disk loading/ejection position but also enables positioning of a disk to be played back onto a predetermined position on the drive base unit. Consequently, a single cam member provides a plurality of functions, thus contributing to the reduction in the number of parts, while realizing a compact and simple construction.
The cam member may have an auxiliary cam surface which is parallel to the cam surface and which opposes the cam surface across the cam follower of the disk holder. In accordance with this arrangement, the cam followers of the disk holders follow the cam surface and the auxiliary cam surface, so as to be guided by the cam surface and the auxiliary cam surface both from the upper and lower sides of the disk holders, whereby the reliability of operation is improved.
The playback apparatus may further comprise a stock arm rotatably disposed on a position on the stage unit adjacent to the disk loading/ejection means, the stock arm having a pressing portion which when the stock arm is rotated forces the disk inserted through the disk insertion section deeper into the disk holder, the stage unit having urging means for rotationally urging the stock arm in the disk force-in direction, the urging means being movable in the disk insertion/ejection directions and having a resilient member for adjusting the urging force.
With this arrangement, a buffer member provided on the urging means regulates the urging force, so that the load applied to the disk by the stock arm can be maintained constant regardless of any fluctuation in the disk diameter or dimensional errors of the mechanical parts, thus ensuring stable operation for forcing the disk into the disk holder.
The disk holder may have a locating member. In such a case, a locating support portion is provided in the vicinity of the disk holder for supporting the locating member of the disk holder when the disk holder has been selected for disk loading or ejection.
With this feature, any rattle or play or other unstable behavior of the disk holder is avoided during loading or ejection of the disk, by virtue of the locating support portion that supports the locating member on the disk holder, whereby the loading or ejection of the disk can be performed stably.
The disk playback apparatus may further comprise a pair of disk detectors disposed at the side of the disk loading/ejection means adjacent to the disk insertion section, the disk detectors being spaced a distance greater than the diameter of the 8-cm disk but smaller than the diameter of a 12-cm disk.
When a wrong member such as an 8-cm disk has been inserted through the disk insertion section, at least one of the disk detectors fails to detect such a member, thus detecting the insertion of the wrong member. When insertion of such a wrong member has been detected, the disk loading/ejection means is prevented from operating, thereby avoiding malfunction or other trouble which otherwise may be caused, whereby the reliability of operation is further improved.
The disk loading/ejection means may include a loading roller and an idle roller which cooperate in nipping the disk therebetween from the upper and lower sides of the disk. In such a case, the disk playback apparatus may further comprise an upper disk guide and a lower disk guide which are disposed near the loading roller at the side thereof adjacent to the disk insertion section. The idle roller is movable into and out of contact with the loading roller and urged by resilient members into contact with the loading roller. The upper disk guide or the lower disk guide has one end engaged and supported by the shaft portions of the idle roller.
In this arrangement, the upper disk guide or the lower disk guide is supported at its one end by shaft portions of the idle roller, so that the disk when inserted can stably be guided into the nip between the loading roller and the idler roller, by the effects of the upper disk guide and the lower disk guide.
The disk playback apparatus may further comprise a side disk guide arranged at the side of the disk loading/ejection means and operative to guide the moving disk from the left and right sides of the disk.
In this arrangement, when the disk is being loaded, the side disk guide ensures that the disk is introduced to a predetermined position in the disk holder, whereas, when the disk is being ejected, ensures that the disk is fed back into the gap between the loading roller and the idle roller.
The disk payback apparatus may also be constructed such that the drive base unit includes: a turntable unit for carrying the disk to be played back; a spindle motor for rotationally driving the turntable unit; chucking means for chucking the disk to fix the disk on the turntable unit; a pickup unit movable in the radial direction of the disk to detect signals recorded in the disk; chuck-releasing means for dismissing the chucking of the disk by the chucking means in accordance with the movement of the pickup unit towards the turntable unit; and position detecting means for detecting that the pickup unit is set at an initial position or at the chuck-releasing position.
This arrangement offers the following advantage. In case of an accidental control failure of the apparatus, the safe operation may be failed if the operation is restarted after recovery of the control function without accurately knowing whether the pickup unit is held at the initial position or the chuck-releasing position at the time of recovery of the control function. In accordance with the above-described features, it is possible to accurately determine whether the pickup unit is held at the initial position or the chuck-releasing position, so that the operation can safely be performed after the recovery of the control function, thus offering further improvement in the reliability.
The disk playback apparatus also may be constructed such that the drive base has a rack, and the drive conveyance means includes at least two drive gears for selectively engaging with the rack to cause the movement of the drive base unit, the gears being spaced from each other by a distance smaller than the length of the rack.
With this arrangement, the driving of the rack can be performed in a shared manner by means of a plurality of drive gears. This permits the rack to have a length smaller than the stroke of movement of the drive base unit, thus contributing to the reduction in the size of the apparatus.
The disk playback apparatus also may be constructed such that the disk holder has a partition plate that covers part of the upper surface of the disk, the partition plate having an arcuate inner edge which is notched to clear protrusions formed on an adapter for setting an 8-cm disk.
With this arrangement, the partition plate of the disk holder can clear the protrusion of an 8-cm disk adapter, by virtue of the notches. This permits the disk holder to have a reduced thickness, thus further contributing to the reduction in the size of the apparatus.
These and other objects, features and advantages of the present invention will become clear from the following description when the same is read in conjunction with the accompanying drawings.